Türkiye Jeoloji Bülteni

Application of Enhanced Local Wave Number Technique to the Total Field Magnetic Anomalies for Computing Model Parameters of Magnetized Geological Structures

Abstract: In this study, enhanced local wave number (ELWN) technique is presented to compute some modelparameters of isolated and magnetized geological structures such as horizontal position (exact origin), depth andsource geometry using the total field magnetic anomalies (TMAs). The technique uses analytical signal amplitude(ASA) and first- and second-degree horizontal and vertical derivatives of observed TMAs, and then simply computesthe model parameters without requiring a priori knowledge about the nature of the causative magnetized body.Additionally, inclination and declination angles of both magnetization and ambient field have no effects on theresults. In the ELWN technique source geometry, viz., structural index (contact/fault, dyke, horizontal cylinder andsphere) is determined using the depth and exact origin computed previously. Hypothetic simulations performed usingTMAs due to some simple shaped geological models have showed the ability of the technique. Moreover, an actualmagnetic data taken over the Kesikköprü iron deposit (Central Turkey), one of the largest iron reserve in Turkey,has been also analysed. A depth of 21.39 m has been computed for the magnetized geological source which includesthe mafic rocks rich in magnetic properties, and the iron ore body. The structural indices obtained have indicated adike-like or an intermediate form between a dike and a horizontal cylinder body for the magnetized source. Thesefindings are compatible with those of a recently published study. Hence, the use of ELWN technique is proposed forrapid and reliable model parameter estimations from TMAs as an alternative or supportive experiment to the inversemodelling studies.